Solved Weird "Bubbles" sometimes?

I have had my Robo 3D R1 for a few days now. Getting it honed in pretty well. Wondering if anyone else has any issues on some prints that have like some bubbles. It's not like extra filament I don't believe. It looks like the top of a lego piece. Like the little knobs. They don't stick up nearly as far as the lego knobs but they are there on some prints. I can't get a picture until I get back home from work. Has anybody else experience this issue?

 

Could be a couple of things.

1. Bad filament. No one seems to be a fan of the filament the robo comes with.
2. Your top layer height is insufficient. You probably need to get the top layer thickness up to 1.2mm. Google 3d print pillowing.

There are some great visual guides to print problems out there.
http://forums.robo3dprinter.com/index.php?threads/visual-troubleshooting-guide.3017/

 

Thank you for that. I wasn't sure what to call it but it does look like pillowing. I will look into it and let you know how it goes.

Edit: It seems that I need to adjust my top layer height. How do I go about this in Cura? I'm printing at 0.1mm for my parts. Also I'm really new to 3d printing but found that I like Cura the best so far. Also my fan is disabled because I'm printing with ABS. Do I need to enable it for the top layer?

 

Under the basic tab in the fill section the first line is for top/bottom layers. Set this to some multiple of your layer height.

 

So since my layer height is .01mm I should do like .02, .03, .04 etc.. Is this correct? What would you suggest my top layer height should be? Also if increasing the top layer height increases the bottom layer height as well will this create visible lines on the bottom layer like show in the picture from the link you posted?

 

I hope you mean you are printing with a layer height of 0.1mm.

A height of 1.2mm is sufficient. If you are concerned about print time you might be able to go as low as 0.8mm.

 

Woops. I meant 0.1. My bad. I'm not to worried about print time since i'm printing at the lowest layer height anyways. I will adjust that when my current print is finished and see how it turns out. Thanks for your help. Unless there is a way to adjust it while it's printng.

 

what you need is sufficient layers to fill the top. for a .1 I go 10+ layers depending on bridging qualities of my filament. More won't hurt. just takes longer/more filament. Do 1mm or so of top layering is what you end up doing. .1 10 layers... 1mm.

Btw.. I got great prints out of the robo filament. It was dry and smooth.

 

I'm using some cheap ABS I got from Fry's Electronics. Haven't had any issues with it at all except for a little pillowing here and there which I'm sure this settings change will solve. $24.99 for 1kg. Can't complain so far. I will update with pictures in about an hour.

 

like some others have said... there's not a "bad" filament out there... old days there was junk with inclusions in the filament.. but so far , as a purchaser of the cheapest stuff I can find, I have found that it is hit or miss... higher price is MORE LIKELY to be nice and dry. Neutral colors seem to be best (neutral as in un-colored)

 

Here are the pictures. It definitely looks like pillowing. Also how do I fix the mess inside of the arrows? Any other issues or suggestions you guys have?

 

Seems like pillowing to me.

Correct me if I am wrong, but those arrows are on the bottom of the print as printed? If so you are seeing the bridging sag from one side to the other as the printer lays down filament. Having the fan on for bridging (and PLA in general) should help some. Another option would be a design change. Instead of having the arrows recessed, just recess the outline of the arrow.

 

do you have support for the arrows?
It won't "cure" it.. but it might help... other fixes include, printing from a different orientation.

increase your top layers to like... 10 or 15

 

It's not my design. It's the Vend candy dispenser. I should have switched the that piece 180 degrees so the arrows would have been printed last? I'm almost done printing some more parts after changing the top/bottom layer height. Does my Z height and stuff look ok though? It's set at 1.0 in the start Gcode.

 

looks good enough.. you'd have to measure to be sure.. but fractions of a mm.
Setting your first layer extrusion height/percents will have a pretty big impact on the adhesion and flatness of your first layer. The offset will cause your height to be the difference from expected and actual with adjust your print height that much.

Fipping your part upside down would mean a lot of support wouldn't it? Its always a balancing act..

I know I used to get really good supported surfaces, but with S3D I get slop for my supported layers. I have to figure that out.

 

The biggest reason to mess with the z height offset is to get better bed adhesion. Our good friend @PrintedSolid has a good blog post that goes into greater detail.

http://www.printedsolid.com/firstlayer/

If your prints are sticking and you are happy with the appearance leave it alone. If you want that bottom layer to appear filled in a little more you can drop the z offset a little.

 

I have to agree that that would be the "biggest" reason to mess with it. But technically speaking, there's a right height and other than right.
I have lowered my z offset a bit to make it stick better.. but other settings would be more "correct".

 

I have no issues with parts sticking. I use painters tape then put purple glue stuck down. Not one part has lifted (yet). Nozzle at 235 an bed at 80. So I shouldn't mess with the height then? Kinda wanted a more solid look instead of the layers/lines being as noticeable like the rest of the part.

 

ABS yea? Sounds good.